1. Field of the Invention
The invention relates to quick release buckles for backpacks and the like.
2. Description of the Relevant Art
Web straps on light weight backpacks, rucksacks and hiking packs typically use xe2x80x9cside-actionxe2x80x9d buckles to allow shoulder, compression and/or large pocket straps to be parted. This side-action buckle design has significant limitations when used in this capacity. The release tabs are recessed onto the sides of the buckle so they can be difficult to find and release when hurried or when wearing winter gloves. Both release tabs must be squeezed simultaneously toward each other to part the buckle. The hand force required to push the halves together and lock them cannot be increased/decreased without a proportional impact on the hand force required to unlock them. When separated, the exposed locking tabs of the male-half (tongue) of the buckle can be easily broken off and the female-half (body) can be crushed if stepped on. U.S. Pat. Nos. 5,832,573 and 6,154,936 are believed to be the most relevant prior art.
The present invention is directed to a simpler more rugged buckle for use with load bearing webbing, e.g. for backpacks, such as used in the military.
The quick release buckle described in the ""936 patent achieves its performance goals as stated in that disclosure. However, it was discovered that when buckle is down-sized to a one inch strap size or less, in some situations the locking fingers do not have high enough stability to manage high tensile loadings. The locking fingers must be of a minimal length to be flexible enough to snap around the keeper yet stiff enough to not distort to the point where they loose their grip on the keeper surfaces when the buckle assembly is subjected to high loads. For larger buckles, the ratio of finger cross-section to length can be managed. Briefly, the locking fingers are long enough to allow the cross-sections to be robust enough to handle high loading.
In the present invention, the moving locking fingers of the ""936 reference are not present. The secure part is characterized by cross-brace guards/guides that provide the structural stability needed to facilitate very high load bearing on the secures locking surface. The body and flex surface of the keeper part is modified from the prior art device such that the keepers are configured such that the cover is pushed upwardly as the secure part is inserted and the keeper snaps downwardly to lock when the secure part is fully inserted. The insertion force and release force are both dependent upon the stiffness of the keeper""s cover. This provides for high load bearing in small buckle applications. The leading guards/guides on the secure part flex against centered load posts on the keeper.
When fully inserted, the keeper""s top snaps down to lock the two parts together while the guard/guides are flexing under insertion loading. When the insertion force is removed, the guard/guides continue to push the secure part against the keeper eliminating any rattle. While under tension from the guards/guides, when the keeper""s lever is pulled upwardly and the buckle assembly is not under tension, the secure part is forced back and away from the keeper unlocking the buckle.
Another feature of the invention is that debris such as snow, ice, dirt, etcetera will be ejected both as the secure is inserted into the keeper part where the debris is pushed out of the top of the keeper through an opening. The leading edge of the guides/guards pushes the debris to the back of the keeper where the curved profile of the back wall forces it upward and outward through openings in the top of the keeper""s flex lever. When the secure is withdrawn from the keeper, the guards/guides carry before them debris which is withdrawn from the keeper and discharged. The flex guards drag the debris from the keeper.
In another embodiment of the invention, a strap locking system is formed either at the rear portion of the keeper and/or secure. At the rear portions of either or both the keeper and the secure are slots in which slots are formed saddles. Straps which secure the keeper and secure pass through and over (are looped around) the saddle. Usually one strap is stitched (fixed) in place and the other end is adjustable. To adjust the strap, the secure is angled, the pinch pressure is reduced, the strap can slip over the saddle until the desired length is reached and the secure is released and the pinch restored. With a lanyard buckle, pulling the lanyard typically rotates the buckle. This movement inherently tends to slip the strap. In this embodiment, teeth angled at 45xc2x0 are formed in the saddle. When the lanyard is pulled as the buckle turns, the teeth rotate and seat into the strap preventing any movement. After the teeth seat and the buckle returns to its normal position it is subjected to intermittent loads during normal use.
With prior art buckles, these intermittent loads cause the adjustable strap to slip or loosen and the strap must be continually adjusted. With the present invention, the teeth prevent this slippage.
Therefore, the teeth prevent slippage under two distinct conditions, when the secure is released from the keeper by the lanyard action and during normal use with intermittent loads.